In looking at the Phase 1 sheet, I see that endive and cabbage (red, pak choi,
bok choy) are on the list for vegetables allowed in the daily 4 cups. Oysters are also on the allowed Dinner Protein list, but it doesn't say anything about canned. I would imagine it depends on what are in the ingredients, and what liquid they are packed in.
Just in case you need the sheet:
http://www.3fatchicks.com/forum/4189093-post135.html